Transaction device, equipment and method for protecting account numbers

Abstract

Security equipment protects the relaying of account numbers and personal identification numbers (PIN) by telephonic or other communication link. The equipment includes a host computer an a remote portable transaction device that interact. A credit granting institution generates an account number and a series of unique personal identification numbers for each account number. This information is stored in the host computer's memory and is assigned as a reference series to an individual customer account number. An identical series of numbers in the same sequence is stored in the memory of the remote device. In operation, the customer account on the host computer is activated and the host computer's memory is indexed sequentially to the first number in the reference series. During the use of the remote device, a unique personal identification number is added to the customer account number and transmitted to the host computer. There it is compared to the account number and personal identification number in the reference series. The computer will authorize the transaction if the number in the stored series is identical the number in the reference series. Otherwise the transaction will be denied or questioned.